John McGinnis stepped out of his pickup truck and planted his feet in the muddy, ridge-top field with the same determination he has used to plant soybeans and corn for the past 30 years.

Spread before him was a rural panorama of browns and greens under a gray winter sky. Across the narrow country road that borders the field, the forested terrain dipped to touch the Third Mine Branch Run, then climbed back up to meet another open brown patch of farmland riding the top of the next ridge.

"It just don't make any sense to put golf courses and a housing development on that," Mr. McGinnis said.

Not everyone sees it that way. A York, Pa., developer wants to build two professionally designed 18-hole golf courses and up to 500 houses on 970 acres between Ensor Road and Interstate 83. It would be, by far, the largest development to go into rural northern Baltimore County, typically defined as the area from Hereford to the Pennsylvania line.

"If this kind of development is approved, the pressure will be on farmers adjacent to it to also sell," said G. Richard Curran, the county agriculture extension director. "This development could be a real setback to all the attempts to preserve agricultural land in the area."

Developer Robert L. Redcay said that he intends to preserve as much of the area's pastoral character as possible in designing the Mine Branch Golf Community.

Also, a study by the county's Department of Recreation and Parks indicates that the county needs more public access golf courses. Baltimore County has five public golf courses, compared to 16 in neighboring York County, Pa.

But Mr. Redcay's proposal, as it stands, would conflict with the county's master zoning plan.

Development during the last few years in northern areas of the county has risen mainly in pockets west of I-83, primarily on land zoned RC-5, which allows one house per 1.3 acres.

But the Mine Branch development would be on the east side of the highway, where the land is zoned for much less density.

Much of it is zoned RC-2, an agricultural preservation zone that allows only one house for each 50 acres, with some RC-4, which allows one house for every five acres.

The developer has requested that the entire tract be rezoned RC-5.

"There is RC-5 zoned land just on the other side of I-83, and it would seem logical to extend it over the expressway and to cover our site," says Tom Church, the engineering and design consultant for Mine Branch.

BWI Development Corp., the firm Mr. Redcay heads, has applied for a zoning change during the county's comprehensive rezoning process, which is done every four years. The county planning department will hold hearings on this and other requests in April before making recommended changes in the zoning plan to the County Council.

The developer has the option to buy the largest piece in the proposed development tract, 400 acres known as the Rosenbloom property. A 270-acre parcel, a former landfill, is owned by Baltimore County.

Another 170 acres is owned by the Carski family, and the fourth parcel, about 150 acres, is owned by Dr. Robert L. Kondnor. Both owners have agreed to join Mr. Redcay as partners.

County officials aren't saying whether they think the developer will get the necessary zoning change.

Councilman C. A. Dutch Ruppersberger III, a 3rd District Democrat who represents the area, declined to comment directly on the project. He did say that in the past, he has not generally favored rezoning agricultural land for development. He also said that the burden rests with the developer to win the approval of residents.

Such approval won't come easily.

"If the county permits [rezoning], then some other developer will buy up property adjacent to the site and say it would seem logical to rezone that land RC-5," says Dr. Richard W. McQuaid, president of the Maryland Line Area Association, a community group. "And then where would it all end? Everything would become RC-5."

The community association fought unsuccessfully three years ago to keep an industrial park from being built in the area. It is also appealing the county's approval for a housing development along Cameron Mill Road just west of I-83.

Lucy Ikeler, vice president of the Citizens Alliance for Northern Baltimore County, said that northern residents are following closely the proposed development "because its impact could go far beyond just the Parkton-Maryland Line area."

Mr. Church said that the developer would welcome the opportunity to explain the project to residents.

"We plan to preserve the natural trout stream beds in the tracts, for example, and except in a few isolated spots, keep a screen of trees around the development," he said. "We'll cut down as few trees as possible."

The development would be roughly one-third golf courses, one-third single-family homes and one-third open space, Mr. Church said.